DNA fingerprinting reveals genetic secrets of cannabis strains

This forensic research paper presents a breakthrough method for identifying and comparing cannabis samples using ISSR-PCR (Inter-Simple Sequence Repeat-PCR), a DNA-based genetic fingerprinting technique. Researchers analyzed 48 cannabis samples from 24 strains and developed numerical scoring systems to determine whether different cannabis samples are genetically identical, from the same strain, or completely different. This is crucial for law enforcement investigations, as it allows authorities to link seized cannabis samples to specific cultivation operations or previous confiscations.

The study established two key numerical indicators for measuring genetic similarity: a "similarity score" ranging from 0-10, and a "total likelihood ratio" that provides statistical confidence in sample matching. The results showed clear separation between groups: identical samples scored 9.48 on the similarity scale, samples from the same strain averaged 4.34, while different strains averaged only 1.69. The likelihood ratios demonstrated extraordinarily high discrimination power (up to 10⁷⁹), meaning the method can reliably distinguish between cannabis sources with exceptional accuracy.

The practical implications of this research extend beyond law enforcement to include plant breeding programs, cannabis quality control, and authentication in emerging legal markets. By establishing objective, numerical criteria for cannabis sample comparison, this method provides a standardized forensic tool that could help track cultivation operations, prevent counterfeiting in legal dispensaries, and support breeding programs that aim to maintain consistent genetic profiles of specific strains.